A dog's eyes are similar in structure to our own, with a couple exceptions—one being a third eyelid called the nictitans. This thin shutter protects the eyeball from tall grasses and environmental pollutants, as your dog romps and plays. The third eyelid also has a tear gland located deep within its tissues, called the third eyelid gland (TEG). Each eye of a dog actually has two tear glands—also called lacrimal glands— unlike people who have one.

Cats also have a third eyelid that closes from the side and appears when the eyelid opens. This membrane partially closes if the cat is sick, but it is often visible in cats that are sleepy and content. If your cat regularly shows its third eyelid, it's time for a visit to the vet.

Signs of eye problems in dogs and cats

If you notice a discharge or red irritated eyes, or if your pet rubs its eyes with a paw or on the ground, don't delay—please seek expert advice as soon as possible.

Possible signs of infection or disorder:

  • Mucus or gray discharge indicates an irritation or allergies; yellow or green discharge indicates infection
  • Red inner lids can indicate infection or irritation
  • Redness in white of eye can indicate glaucoma, inflammation or deeper infection
  • Cloudiness can indicate cataract or injury
  • Difference in pupil size can indicate a tumor, nerve problem or inflammation
  • Aversion to light
  • Bulging of the eye may indicate tumor, abscess or glaucoma
  • Squinting equates to discomfort, possibly from a foreign body, scratch or infection

Natural Treatments for dogs and cats with eye disorders

Good nutrition plays an important role in the overall health of your pet and can help to maintain healthy eyes and vision. When an animal has severe vitamin deficiencies or is malnourished, cataracts and other eye disorders can develop.

There are several vitamins, herbs and other nutrients that help to nourish the eyes:

Vitamins A, C and E have antioxidant properties which fight free radicals that can damage the lens of the eye.

Bilberry extract is derived from a fruit similar to the blueberry and contains active ingredients for eye health and proper vision. The berries are rich in the antioxidant anthocyanosides -- the red pigments that are beneficial in ophthalmology and vascular diseases. Nicknamed "the vision herb" bilberry has a substantial body of research that confirms its benefits for eyes. In addition, bilberry helps support circulation which is especially beneficial for pets with eye problems related to diabetes. 

Zinc is a mineral linked to good vision and may protect eye tissue from damaging light and inflammation. Zinc is found in healthy retinal tissue.

Lutein, a carotenoid found in dark, leafy greens, is also found in the retina of healthy eyes where it acts as a shield against harmful light and may help protect the eyes against damage from ultraviolet radiation.

Mixed Carotenoids contain antioxidants found in carotenoid-rich food, that is, produce that are rich in color. Two specific carotenoids, lutein and zeaxanthin, provide antioxidant protection in the macular region of the ey and have been found to reduce the incidence of cataracts.

Astaxanthin is an antioxidant that is especially beneficial for aging pets in that it helps support the immune system, cardiovascular system and eye health.